Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

20. Carbohydrates

Cyclic Structures of Monosaccharides

GOB Chemistry

20. Carbohydrates

Cyclic Structures of Monosaccharides

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Multiple Choice

D-ribose is an aldopentose sugar that is found in the DNA. It commonly exists as a five-membered β anomer. Draw D‑ribose in its cyclic hemiacetal form.

cyclic hemiacetal

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Identify the structure of D-ribose in its linear form. D-ribose is an aldopentose, which means it has five carbon atoms and an aldehyde group. The linear structure shows the aldehyde group at the top and hydroxyl groups on the other carbons.

Understand the concept of hemiacetal formation. A hemiacetal is formed when an alcohol group reacts with an aldehyde group within the same molecule, leading to a cyclic structure.

Recognize that D-ribose commonly forms a five-membered ring, known as a furanose form. This involves the reaction between the aldehyde group at C1 and the hydroxyl group at C4.

Determine the orientation of the hydroxyl groups in the cyclic form. In the β-anomer, the hydroxyl group on the anomeric carbon (C1) is on the same side as the CH2OH group at C5.

Draw the cyclic structure of D-ribose in its β-anomer form. Ensure that the ring is a five-membered furanose, with the oxygen atom in the ring and the correct orientation of the hydroxyl groups as per the β-anomer configuration.